1. Field of the Invention
The invention relates to a packer apparatus for use in subterranean oil and gas wells.
2. Description of the Prior Art
Well bore packers are frequently utilized in well casings, with a tubular string of running and retrieving pipe or tubing associated with the packer and held in tension during setting and retrieval. In environments where there may be considerable temperature variations, causing expansion and contraction of the tubing conduit, there may be loss of integrity of setting and sealing elements of various down hole tools.
In U.S. Pat. No. 3,256,437, issued June 14, 1966, entitled "High Temperature Well Packer Apparatus", there is disclosed a packer apparatus which is particularly adapted for use in high temperature well bores, where temperatures are from between about 400.degree. F., up to and sometimes exceeding 700.degree. F. A feature of that prior art packer which enables its use in high temperature wells is that a sealed tubing member or "slick" joint extends through the body of the packer and can be released from the body to allow the tubing to be "spaced out", with the slick joint thereafter being free to allow for expansion and contraction of the tubing string. The packing and slick joint seal can be periodically retightened to prevent leakage, and the packer assembly is retrievable.
In U.S. patent application Ser. No. 863,871, filed Dec. 23, 1977, Eugene H. Bigelow, et al, inventors, entitled "High Temperature Well Packer", an improved apparatus combines the features of the aforesaid patent which is set in the well casing and retrieved therefrom by taking a pull on the tubing string, but without requiring rotation of the tubing string except to release a control device when the packer is initially set in the well bore and to release a connection between the packer body and the tubing to allow the tubing to be spaced out.
The present invention provides an improvement over each of the above prior art devices. The present apparatus provides means for anchoring the apparatus onto the interior wall of the casing to prevent both upward and downward longitudinal movement within the well. Additionally, means are provided to continuously energize the packing assembly as a result of differential pressure being transferred in the tool and applied thereacross. Furthermore, the present apparatus energizes the packing assembly without applying a load across critical components of releasing means utilized to disengage the slick joint from the interior of the packer body.